ARRS: Twice Yearly Mammograms Best After Lumpectomy

Action Points

Explain to patients that this study suggests that more frequent mammography may detect earlier-stage breast cancer recurrences in patients who have had conservative surgery for primary breast cancer.

The findings are based on a retrospective review of medical records, not a prospective clinical study.

Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered preliminary until published in a peer-reviewed journal.

SAN DIEGO -- Breast cancer patients who had recurrences after lumpectomy had less advanced recurrent tumors if they adhered to a semiannual mammography schedule, data from a large retrospective case review showed.

Semiannual screening was associated with an almost 30% increase in the proportion of recurrences detected in stages 0 or 1 compared with annual follow-up, according to a presentation here at the American Roentgen Ray Society meeting.

Additionally, recurrences detected by more frequent mammograms tended to be25% smaller, according to Vignesh Arasu, MD, of the University of California San Francisco, and colleagues.

"Our results are not definitive proof that more frequent mammographic surveillance will improve outcomes, but they do suggest that these women may need to be treated differently from women in the general population who have average risk," Arasu said in an interview.

Between 10% and 20% of breast cancer patients have recurrences or new primary tumors in the ipsilateral breast after lumpectomy. Recurrent disease increases the risk of breast cancer mortality by as much as 300% compared with the initial tumor, said Arasu.

The optimal frequency of mammographic follow-up after lumpectomy has not been determined, although many patients have annual mammography.

"Most national organizations recommend annual mammograms beginning at age 40 for average-risk women," said Arasu. "Women who have been treated for cancer have a much higher risk of breast cancer than the general population. It makes no sense that they would follow the same mammography schedule as women with no history of breast cancer."

To examine the influence of mammogram frequency on outcomes, Arasu and colleagues reviewed the experience with their institution's post-lumpectomy surveillance protocol, which calls for semiannual mammography of the ipsilateral breast for the first five years after breast-conserving surgery.

Investigators reviewed records on patients who had conservative breast cancer surgery from 1997 through 2008. Mammography intervals of four to nine months were considered adherent with the institutional protocol, and intervals of nine months or more were considered nonadherent.

The analysis included 10,750 mammography examinations in 2,329 patients. Abnormalities were identified in 158 (1.5%) of the mammograms, leading to detection of 114 cancers and a positive biopsy rate of 72%.

The mammographic examinations consisted of 7,140 (84.8%) exams that met criteria for compliance and 1,281 judged to be noncompliant, including 1,065 that investigators considered representative of annual surveillance.

Semiannual mammography detected tumors that had a median size of 11.7 mm compared with 15.3 mm for annual surveillance (P=0.148).

Additionally, 98% of new cancers identified by semiannual surveillance were node negative compared with 91% of cancers identified by annual surveillance (P=0.276).

"Obviously, the outcome of greatest interest is survival, but that takes many years of follow-up in thousands of women to assess," Arasu told MedPage Today. "What we can do is look at predictors of survival. One of the predictors is the size or stage of the cancer recurrence, just as it is in primary breast cancer. The bigger the recurrent tumor, the worse the outcome is. Our results sort of imply what the outcomes are."

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